Embodiments of the present invention relate to a transmission device for two electric impulse measurement signals and to a sensor system.
A sensor system may be a photodiode array or a pixel array, for example of a positron emission tomography system for gamma ray detection in medical technology. Every pixel of the pixel array or in general every sensor element outputs a measurement signal when registering a measured quantity or value, e.g. as a result of light incidence or a light pulse. With such applications the measurement signal typically is a so-called single-ended measurement signal. A single-ended measurement signal is an electric signal, like, e.g., a current signal relating to a determined reference signal, like, e.g., a mass signal (applied to a mass conductor), and which may be transmitted using one single signal conductor.
With a high integration density of integrated circuits, singled ended measurement signals frequently lead to crosstalk between the individual circuit blocks and thus between the individual channels, in particular when analog and digital functions are realized simultaneously. In analog circuit technology, such crosstalk may be reduced or prevented by using differential measurement signals. A differential measurement signal transmits the respective signal information on the measured quantity using two signal conductors, wherein the actual signal is a voltage difference or current difference between a first signal portion (transmitted via the first signal conductor) and a second signal portion (transmitted via the second signal conductor). It has no effect on the voltage difference here (on signal information) if, for example, the average value of the first and second signal portions varies due to external interferences which makes the differential measurement signal very resistant to interferences. In order to utilize these advantages in the above-mentioned sensor applications, frequently the singled ended measurement signal of the individual sensor element is converted into a differential measurement signal. There are different circuits or members for such a conversion, like, e.g., a single-ended-to-differential converter (explicit circuit). Alternatively, also a differential amplifier may be used in this respect comprising typically at least two input transistors which contribute to noise in signal processing and increase the total energy demand.